Question: Nadia is 4 times as old as Christopher and is also 24 years older than Christopher. How old is Nadia?
Answer: We can use the given information to write down two equations that describe the ages of Nadia and Christopher. Let Nadia's current age be $n$ and Christopher's current age be $c$ $n = 4c$ $n = c + 24$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $n$ is to solve the second equation for $c$ and substitute that value into the first equation. Solving our second equation for $c$ , we get: $c = n - 24$ . Substituting this into our first equation, we get the equation: $n = 4$ $(n - 24)$ which combines the information about $n$ from both of our original equations. Simplifying the right side of this equation, we get: $n = 4n - 96$ Solving for $n$ , we get: $3 n = 96$ $n = 32$.